The purpose of this project is to develop the detergent treated smooth muscle as an experimental model to study the regulation of tension. The chemically skinned muscle will then be used to investigate the roles of ions and substrates on the tension generating process. Cross bridge activity will be inferred from measurements of tension, stiffness shortening velocity and length-tension relationships and the effects on this activity of the different ions and substrates. These data will then be correlated with information on filament structure and formation obtained from ultramicroscopic examination of the chemically skinned smooth muscle.